Updated Neuromotor 2024 Lectures 3(1) PDF

Neuroscience 6th Edition Dale Purves at al. 2018 Principles of Neural Science 6th Edition 2021. Reviews to be posted into Teaching Folders.  Neuromotor Part 2 (lectures 3-4_ 1) Recap of key points form Lts 1-2 – Answering Questions 2) Compound muscle act...

Neuroscience 6th Edition Dale Purves at al. 2018 Principles of Neural Science 6th Edition 2021. Reviews to be posted into Teaching Folders.  Neuromotor Part 2 (lectures 3-4_ 1) Recap of key points form Lts 1-2 – Answering Questions 2) Compound muscle action potentials and motor unit recruitment - latency period in recoding tension Vs electrical activity. 3) What benefits can we see from exercise – intense and endurance types of exercise 4) Three levels of input control that regulates the a-motor neuron neural activity output to muscle 5) Sensory receptors that monitor muscle and movements = Proprioception 6) What is the major proprioceptor for sensing and controlling movement ? 7) How are motor neurons organized within the spinal cord 8) How do groups of motor neurons (motor pools) work together to mediate movement ? The role of interneurons – as seen in complex reflexes. Key components of neuromotor circuits. 9) What is reciprocal inhibition?  1) Recap of key points from Lts 1-2 Know the pre and postsynaptic features of the Neuromuscular Synapse Explain out how a muscle action potential is generated Explain the Safety factor How do inhibitors to aceylcholine esterase lead to improve muscle strength in patients with Myasthenia Gravis ? What is fiber type grouping? And how could it lead to a loss of overall muscle tension for a given muscle Answering Student Questions  My videos Action Potential at the Neuromuscular Junction https://www.youtube.com/watch?v=tCTykJtGWx4&t=503s Henneman's Size Principle https://www.youtube.com/watch?v=-LsXDvA3EmY Sensory (Proprioception) Sensing and controlling body position and movement Proprioceptors  Anatomy and function of Golgi Tendon organs Golgi tendon organs are low-threshold mechanoreceptors found in tendons; they provide information about changes in muscle tension. Muscle Spindles are the main proprioceptors Bag – Ia and II Sensory neurons Bag g-MN dynamic and Static Chain II sensory neurons, gMN static MN =Motor Neuron  The function of g-motoneurons is to ensure sensitivity to stretch of muscle spindles during all phases of muscle contraction a-motor neuron activation without g motor neuron a-motor neuron activation with g motor neuron Purves D 6th Ed Neuroscience Upper Motor neuron pathways can co-activate a and g motor neurons – which can increase sensory feedback to muscle to alter reflexes The increased activation of a and g-motor neurons can come from upper motor centers (Higher centers). These additional inputs are important for the modification of reflexes – as some act to facilitate the stretch reflex and some can of these inputs and act to inhibit it Co-Activation of alpha (a) and gamma (g) motor neurons during voluntary movement is enhanced by upper motor centers Upper Motor neuron pathways can co-activate a and y motor neurons and with training can increase the instantaneous firing rate of a-MNs and muscle responses The Motor neuron – Muscle Spindle Circuit +  Record sensory neuron Record sensory Interneuron + Record Record Motor Motor Neuron Neuron (Extensor) (Flexor)  In normal life the monosynaptic reflex is constantly active at a low level. It helps to keep a muscle at a fixed length despite varying loads. Copy sent to cerebellum * * Lower limb to clark’s N - synapse to cerebellum spinocellbellar tract to cerebellum Upper Limb to cuneate N – synapse relay signals to cerebellum Purves et al., Neuroscience, 4th Ed. (2010) Crossed Extensor coupled with withdrawal reflex – an example of a divergent circuit. Neurotransmitters – ACh +ve , Glutamate +ve CNS, Glycine SpC –ve. What happens when you lose Glycinergic neurotransmission (Stiff man syndrome) (Bovine Myclonous – see video)  Learning Objective from lecture 3 Compound muscle action potentials and motor unit recruitment - latency period in recoding tension Vs electrical activity. What benefits can we see from exercise – intense and endurance types of exercise